1. Field of the Invention
This invention relates to a mechanical governor for internal combustion engines, and more particulary to a structure for reducing the reaction force of the governor spring at the control lever thereof.
2. Discription of the Prior Art
In a conventional governor for internal combustion engines, there is provided a control lever, which is associated with an accelerating pedal, for controlling the rate of fuel supply. In such a governor, when operating the control lever from an engine start position or an idling position toward the direction of a maximum position, the reaction force exerted on the control lever is gradually increased since the control lever is biased by a governor spring. Therefore, the control lever may be held at a desired rotating speed position of the engine only by continuously applying a force to the accellerator pedal strong enough to balance the reaction force of the governor spring. Conversely, when the control lever is returned to the start position, the tension of the governor spring is reduced, whereby the control lever is liable to become unstable in the vicinity of the idling position.
Recently, it has been proposed to provide a mechanical governor with a balance spring which is used as a means of reducing the force required to operate the control lever. The blance spring is arranged so that it opposes the force of the governor spring, thereby reducing the required pedal force needed to maintain the control lever at a fixed position. However, if one attempts to adjust the speed regulation of the governor, expressed by N.sub.2 -N.sub.1 /.sub.N.sbsb.1, wherein N.sub.2 is maximum r.p.m. at termination of regulation and N.sub.1 is the r.p.m. of the engine at the start of regulation, the reaction force on the control lever will be altered. This occurs because adjustment is carried out by varying the tension force of the governor spring. If the speed droop of the governor is changed or adjusted to a desired value, it is necessary to adjust not only the governor spring but also the balance spring. However, there is no provision for any adjusting means. That is, when the tension of the governor spring is adjusted, the tension of the balance spring simultaneously changes since the balance point of the control lever varies by the adjustment of the governor spring.